I fired my Spiller and Burr over the weekend. I used 20FFFg under a .380 pure lead ball topped with a layer of bullet lube.
It was a delight to shoot. The gun was quite docile and pointed well. I'm very happy with it and will continue to enjoy this gun.
I did have some issues with the RWS No.10 percussion caps.

They were quite loose on the nipples. I had to squeeze them first before installing them.
Has anyone else experienced this?
Is there a better fitting cap available or different nipples with a slightly larger diameter cone?